Polyclonal Antibodies Can Be Generated Against Almost Any Protein of Interest

Short Answer

Polyclonal antibodies can be generated against almost any protein of interest by repeatedly injecting the purified protein into an animal (such as a rabbit) and collecting blood serum once the animal's immune system has produced antibodies against the protein. In this process, the antigen is not injected alone; it is co-injected with a so-called adjuvant to "trick" the immune system. Additionally, the adjuvant used in the first injection is often different from that used in later "booster" injections. Freund's complete adjuvant (C) contains a water-oil emulsion plus heat-killed Mycobacteria. In contrast, Freund's incomplete adjuvant (I) lacks the Mycobacteria component. Which adjuvant (C or I) do you think is used in the booster injections? Which immune response-primary (P) or secondary (S)-is triggered after the first purified protein injection? Activation of which antigen-specific immune cells-memory (M) or effector (E)-is chiefly responsible for the "boosting" effect of the later injections? Write down your answer as a three-letter string, e.g. ISM.